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Finding the Fourth Proportional to 407.68, 612.48 and 390.88

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Solution

The fourth proportional to 407.68, 612.48 and 390.88 is: 587.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.68 : 612.48 = 390.88 : x
  2. Step 2: Convert to fraction form
    407.68/612.48 = 390.88/x
  3. Step 3: Cross multiply
    407.68x = 612.48 × 390.88
  4. Step 4: Simplify right side
    407.68x = 239,406.18
  5. Step 5: Solve for x
    x = 239,406.18/407.68
  6. Step 6: Final answer
    x = 587.24

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.